Behavioural interaction of Chrysoperla carnea and Mallada desjardinsi against Phenacoccus solenopsis Tinsley

The present study revealed that during a 2 hrs period, no significant differences for the various foraging parameters viz.; prey handling time (total time larva hold/feeding the prey), period of active foraging (total time the larva spent foraging on the cotton leaf/Petri plate), prey capture (time taken by the larva to get hold of the prey) and resting time on the leaf sample were observed by Chrysoperla carnea and Mallada desjardinsi. The foraging period of C. carnea was highest of the third larval stage (44.57 min ± 6.58) followed by first larval stage (42.85 min ± 4.15) and second larval stage (34.72 min ± 11.43). Time spend in capturing the prey was 8.6 min ± 1.17 (3^rd instar), 5.40 min ± 0.51 (1^st instar) and 4.40 min ± 1.80 (2^nd instar). Second larval stage spent maximum time in resting followed by the third and first larval stages. As the prey stage decreased, the foraging time increased. A similar trend was observed for the prey encounter in M. desjardinsi. Interestingly, all larval instars of M. desjardinsi spent more time on resting than larvae of C. carnea. Further, it was observed that the prey-predator interaction varied on size and mobility of the prey as well as the predator. It was also noticed that the total prey consumption was higher in M. desjardinsi than C. carnea. The study indicated the preference of predator for the mealybug stages as well as ability of both the predators to prey voraciously. Hence, both the predators may be exploited for efficient management of the pest which had overlapping population and generations as well as difficult to control through the application of chemical insecticides.